This invention relates to an improved valve assembly for use in well tools; more specifically, well cementing equipment or the like.
In some prior art types of valve assemblies used in well cementing equipment a poppet type valve is used where the valve body head contains an annular recess therein retaining, in turn, a portion of an elastomeric seal therein which sealingly engages the valve body housing. A typical example of this type prior art valve assembly is shown on page 53 of the 1960 Halliburton Sales and Service Catalog.
Another type of prior art valve assembly used in well cementing equipment has a poppet type valve used therein where the valve body head contains an elastomeric seal adhesively retained thereon to sealingly engage the valve body housing. A typical example of this type prior art valve assembly is shown on page 3846 of Halliburton Services Sales and Service Catalog Number 41 and is illustrated in U.S. Pat. Nos. 3,776,250; 3,957,114; and 4,338,999.
However, these prior art valve assemblies have limitations in use. For instance, where the elastomeric seal is retained in an annular recess on the valve body head of the poppet type valve, high velocity well fluids washing over the valve body head tend to wash the elastomeric seal from the annular recess. In other instances, where the valve body head contains an elastomeric seal adhesively retained thereon, in deep, hot wells where oil based muds are used, the adhesive loses strength thereby allowing the elastomeric seal to wash off the valve body head.